Variable reflectivity mirror assemblies, such as electro-optic mirror assemblies, such as electrochromic mirror assemblies, are known and are widely implemented in vehicles. The reflective element assembly of such a mirror assembly often includes two substrates or glass elements with an electrochromic medium sandwiched therebetween. The back or outer surface of the second substrate (commonly referred to as the fourth surface of the reflective element assembly) may include a silvered coating to provide reflectance of an image. Each substrate is coated with at least one conductive or semi-conductive layer, which conduct electricity to the electrochromic medium from an electrical connector clipped or otherwise fastened or secured at least partially along an edge of the substrate and layer.
An example of a known electrochromic reflective element assembly is shown in FIGS. 1 and 2. The reflective element includes an electrochromic (EC) medium layer 1 sandwiched between conductive layers 2 and a seal 7 at a front glass substrate 3 and a rear glass substrate 4 (and may include other conductive or semi-conductive layers). The substrates are offset so that an upper edge of one substrate and its conductive coating extends above the upper edge of the other substrate, while the lower edge of the other substrate and its conductive coating extends below the lower edge of the other substrate. This offset allows for electrical connection of electrical connectors or busbars 5 to the conductive coatings of each substrate, as shown in FIG. 2. The busbars or electrical connectors or clips extend substantially along the entire upper or lower edge of the respective substrate and coating. However, in order to manufacture the mirror element to obtain the desired offset, one or more offset or stepped spacers or pins 6 (shown in phantom in FIG. 2) must be placed along one of the upper and lower edges of the substrates to properly space the substrates from one another and to provide the offset along the edges when the substrates are placed in an assembly fixture.
As shown in FIG. 3, another conventional offset mirror element includes a coating on one of the substrates which provides a tab out portion 7 for connection of an electrical clip thereto. The substrates are offset in a similar manner as shown in the embodiment of FIGS. 1 and 2 to provide clearance at the tab out portion for the electrical connection. Such an embodiment also requires a stepped spacer or pin to provide the appropriate spacing between the substrates and to set the offset between the edges at the desired or appropriate amount.
Typically, it is desirable to minimize the size of the bezel or overlap of the casing/bezel (or even to eliminate the bezel) which extends around the reflective element of the mirror assembly. The bezel is typically required to extend over the front or first surface of the electrochromic cell or reflective element assembly to cover or hide or conceal, for example, the seal around the electrochromic medium of the electrochromic cell (that typically spaces the front substrate from the rear substrate, such as described in U.S. Pat. No. 6,002,511, which is hereby incorporated herein by reference), in order to conceal or hide the seal (and/or the electrical spring conductors, busbar conductors, clips, connectors and/or the like) which may otherwise be visible, particularly when the electrochromic medium is darkened. An exemplary and effective means for hiding the seal and, thus, minimizing the size of the bezel is disclosed in U.S. Pat. No. 5,066,112, which is hereby incorporated herein by reference. Also, and such as described in U.S. Pat. No. 6,449,082, which is hereby incorporated herein by reference, there is typically an offset to allow the clip or connector to connect to the cell or substrate that may influence the size of the overlap or bezel.
In cells or reflective element assemblies that may provide a small bezel or no bezel, it is often difficult to make electrical contact to the semi-conductive and/or conductive layers of the substrates with a restricted overhang between the substrates. A variety of methods have been used to provide electrical power to the semi-conductive and/or conductive layers of electrochromic cells, such as described in U.S. Pat. Nos. 5,066,112; 6,356,376; and 6,512,264, which are hereby incorporated herein by reference.
Therefore, there is a need in the art for an electrochromic mirror element which overcomes the above disadvantages and shortcomings of the prior art.